[Ultrastructure of the bacterial spores and crystals of various Bacillus thuringiensis serotypes]

Spores and crystals of various Bacillus thuringiensis serotypes were studied by electron microscopy. The serotypes were shown to differ in the fine structure of the exosporium and crystals. The packing parameters of morphological subunits were determined by analysing electron photomicrographs by the technique of optical diffraction and filtration. Some of the strains are characterised by hypersynthesis of surface spore structures. The individual morphological properties of crystals can be used for their differentiation.